Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 4014934 times)

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Online Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73675 on: October 31, 2020, 09:13:31 am »
Specmaster has a P.O.TEL. one, would that make it younger than the P.O. one on "richardsradios"?

Edit: Specmaster will soon have...
Haha, no specmaster won’t soon have unless I can cut a deal and it works. These have a higher accuracy than the Avo 8’s with DC being down to 1%

Just imagine how accurate it could be, with a digital display instead!   :popcorn:
Yes but sometimes it’s not all about accuracy but trend spotting, something needles are far better at, especially in a noisy environment. Also of course if you have a very high impedance DMM, then in the case of decaying signals it is almost impossible to detect the point at which the signal begins to drop off. This is sometimes required to be able to correctly align the IF section of radios for instance. Also of course sometimes you need to monitor the voltage at multiple points using multiple meters and it’s so much quicker to look at a needle than a digital display so for those reasons it makes life so much easier to have few such meters at your disposal. :popcorn:
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73676 on: October 31, 2020, 10:05:21 am »

All these pictures of modern soldering irons are rather different to the first one I used - similar to the ones below. The heat source was the kitchen gas hob.


I have one of those too. Recently, I was mostly hunting for a Really Large iron, and stumbled over a Konvolut as the Germans say i.e. a "job lot" to UK people.

[attach=1]

The Weller is not part of the lot, it is what I had in my portable kit before I got a TS100. It's been modified with a silicone rubber cable for better on-site ergonomics but is too cold for most RoHS solders, so had to retire.

I can't tell the rated power consumption of the big one, it's too rusty. But I'd guess around 300W. It's the one I used for the barrier strip.

The "gun type" Engel-Löter is 60W. I've tried it. Very quick to get hot. Very hot.  :-DD

The pre-electrical one remains to be tested. Being a scout leader, I'd probably opt for open fire to heat it. Just because.

Edit: Of course, the kitchen hob is open fire too, I was more thinking of a wooden fire. Until I remembered I've got another rabbit hole ready for exploring, blowtorches. A Swedish speciality. The petrol ones make me positively super-nervous. I've got one for kerosene too, I'll stick to it.
« Last Edit: October 31, 2020, 10:12:26 am by mansaxel »
 

Offline AVGresponding

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73677 on: October 31, 2020, 10:26:55 am »
Just imagine how accurate it could be, with a digital display instead!   :popcorn:
Yes but sometimes it’s not all about accuracy but trend spotting, something needles are far better at, especially in a noisy environment. Also of course if you have a very high impedance DMM, then in the case of decaying signals it is almost impossible to detect the point at which the signal begins to drop off. This is sometimes required to be able to correctly align the IF section of radios for instance. Also of course sometimes you need to monitor the voltage at multiple points using multiple meters and it’s so much quicker to look at a needle than a digital display so for those reasons it makes life so much easier to have few such meters at your disposal. :popcorn:

This is very similar to the arguments used to justify a preference of analog scopes over digital ones...   :horse:



I'm not long back from the PO, where I picked up a couple of parcels. One is sideways TE; it's an Autel 806 Pro (Saskia's fault, for subconsciously recommending it).

The other is a rather nice Star Trek Bluray box set; the first ten films, with an A4 sized glossy book on the making of them, some stills with storyboards on the reverse, a frame from a 35mm print of each, mounted, a small fold-out poster of the side layout of the Galaxy Class, a Starfleet Command shoulder patch, oh and the films themselves come in a nice hardback book style holder.
Pre-owned, but as-new, and the price while not cheap, would be way less than what this would have been new I suspect (£55 shipped).

Incoming Star Trek binge watch!
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73678 on: October 31, 2020, 10:31:38 am »
The little bar graph at the bottom of half decent DMMs is good enough for trend and peak watching these days.

Edit: nice one with the Star Trek haul. I still remember bunking off work to watch First Contact years ago and finding one of my colleagues doing the same  :-DD
« Last Edit: October 31, 2020, 10:34:27 am by bd139 »
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73679 on: October 31, 2020, 10:51:50 am »
The little bar graph at the bottom of half decent DMMs is good enough for trend and peak watching these days.

Edit: nice one with the Star Trek haul. I still remember bunking off work to watch First Contact years ago and finding one of my colleagues doing the same  :-DD
Yeah, the bar graph is a great help but only in cases where the readings are taken at a greater frequency than the digital readout, like the Brymen 867 for example but even that cannot really compete with a live reading that is constantly re-acting to small changes and also bar graphs suffer from slight persistence which can blur small changes. It is also far quicker to read analogue meters than digital as long as you're not particularly bothered with fractions over/below the whole number. An example of this is a car speedometer, most are analogue and all the digital ones that I've driven all seem to suffer from lag and some persistence on the display. 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73680 on: October 31, 2020, 11:04:31 am »
The bargraph is only useful if the variance you want to watch is close to the fullscale measurement range. If I want to spot a 50mV variance on the 0 to 20V range, then the bargraph probably won't change at all, whereas with an analogue meter the needle movement will be visible.

All arguments about "which is best" are kind of pointless anyway. There are plenty of cases where an analogue meter/scope will be more suitable for the job and just as many cases where a digital meter/scope would be better. It's like arguing whether a hammer or a screwdriver is better - It all depends on the task at hand.

An example of this is a car speedometer, most are analogue and all the digital ones that I've driven all seem to suffer from lag and some persistence on the display.

Sorry officer, I wasn't speeding, my speedo has a lag issue. :) I drive an S2000 with digital display, never noticed any lag up to now.

McBryce.   
« Last Edit: October 31, 2020, 11:07:02 am by McBryce »
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73681 on: October 31, 2020, 11:09:28 am »
The bargraph is only useful if the variance you want to watch is close to the fullscale measurement range. If I want to spot a 50mV variance on the 0 to 20V range, then the bargraph probably won't change at all, whereas with an analogue meter the needle movement will be visible.

All arguments about "which is best" are kind of pointless anyway. There are plenty of cases where an analogue meter/scope will be more suitable for the job and just as many cases where a digital meter/scope would be better. It's like arguing whether a hammer or a screwdriver is better - It all depends on the task at hand.

McBryce.   
Exactly this, it is why older engineers are likely to have a selection of tools in their kit and will choose the most suitable tool to do the job with. Younger engineers will probably have had zero experience with analogue meters anyway.

It is also another reason why I'm showing interest in the Selectest Super 50 meter as its scale is larger than that of an Avo so any such variation is going to be easier to spot.
« Last Edit: October 31, 2020, 11:15:23 am by Specmaster »
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Offline AVGresponding

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73682 on: October 31, 2020, 11:14:12 am »
Hmm... you do realise that all modern cars with "analog" speedometers/tachometers are subject to the same "lag" as they are driven electrically by the ECU and not directly mechanically any more?

I will grant you one thing where analog meters are better; a DMM with a filament lamp mounted on top would look especially ridiculous!

 :-DD
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73683 on: October 31, 2020, 11:19:17 am »
Granted they are, but there is no blurring in the transition from 1 digit to the next and is still far easier to read at a glance your speed.

I don't know, perhaps a digital meter with a lamp mounted on it could be interesting if the meter display was on when the lamp was on as well.  :-DD :-DD :-DD
Who let Murphy in?

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73684 on: October 31, 2020, 11:24:55 am »
Still researching the soldering tin wire market.

One thing is rather strange for me:
Felder Sn60Pb40 -selling to private customers prohibited.
Felder Sn60Pb39Cu1 -no restrictions ?!   :-//

What's up with this 1% replacement Pb -> Cu?
Can anyone report his/her practical experience with this?

OTH
The Balver Zinn bleifrei SN100C- SnCu0,7Ni is reported as the only soldering tin that proofed a NASA reliability test. Nice.  :)
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73685 on: October 31, 2020, 11:33:37 am »
The bargraph is only useful if the variance you want to watch is close to the fullscale measurement range. If I want to spot a 50mV variance on the 0 to 20V range, then the bargraph probably won't change at all, whereas with an analogue meter the needle movement will be visible.

All arguments about "which is best" are kind of pointless anyway. There are plenty of cases where an analogue meter/scope will be more suitable for the job and just as many cases where a digital meter/scope would be better. It's like arguing whether a hammer or a screwdriver is better - It all depends on the task at hand.

McBryce.   
Exactly this, it is why older engineers are likely to have a selection of tools in their kit and will choose the most suitable tool to do the job with. Younger engineers will probably have had zero experience with analogue meters anyway.

It is also another reason why I'm showing interest in the Selectest Super 50 meter as its scale is larger than that of an Avo so any such variation is going to be easier to spot.

I don't consider me being an older engineer but I do have (collected) some analogue meters for special tasks where the analogue movement shows trends better than any sampling digital meter.
I use them regularly especially for controlling currents. Or for voltages in unknown environments where capacitive voltages with almost no power could easily trick a high impedance digital voltmeter but not a low impedance analogue meter.

My analogue meters have (with exception of two analogue multimeters like the AVO) moving iron movements that are good for AC and DC at the same time. Those have advantages over digital meters in certain situations also.
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Online Robert763

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73686 on: October 31, 2020, 12:05:14 pm »
Specmaster has a P.O.TEL. one, would that make it younger than the P.O. one on "richardsradios"?

Edit: Specmaster will soon have...
Haha, no specmaster won’t soon have unless I can cut a deal and it works. These have a higher accuracy than the Avo 8’s with DC being down to 1%

Just imagine how accurate it could be, with a digital display instead!   :popcorn:

Glad you said "could be" too many people blindly trust a digital display. I used to do a lesson with an AVO 8 MkII, AVO DA116 (3.5 DMM in AVO 8 style case) and a PP3 "9V" battery. There was also a 41/2 digit Fluke 8060A and manuals for each meter next to me that I did not mention.  students had to meaure battery with both and draw conclusions.
As the AVO 8 said 8.4V and the DA116 said 9.05V (typical values), All responded that the digital meter was more accurate.

The reality of course is that the 8 MkII is specified to 1% for readings over 50% FSD so "9V" is accurae to 0.09V. and the the DA116 is 0.5% of reading +- 1 count at 20 Deg C so is in theory more accurate. But in practice a 8 MkII 10 years out of cal will be better than a DA116 10 years out of cal. What the students missed was that both the meters should have been within  about 0.15V of each other not nearly 0.5V different. They ASSUMED the 8 Mk II was about 5% inaccurate. In fact the "9V"batery was a rechargable ni-cad with 7 cells, 8.4V and marked as such. The DA116 hd been deliberately adjusted to read high (and had a "DO NOT USE" label on it)
Very few stucents ever spotted the 8.4V battery or asked to see the manuals or use the Fluke for confirmation.
A particular issue with digital meters is AC accuracy away from 50/60Hz. The DA116 is 1% +- counts at 50/60Hz, the 8 MKII is 2.25% BUT is good for 25 to 2000Hz. This means that for work on aircraft sytems at 400Hz the 8 mkII is more accurate and the DA116 completely out of scope.
This is also true of modern lower end Flukes. I saved a suppler from having to re-do two days of acceptance testing on a bit of kit because I was witnessing the test and spotted they were using a Fluke 75 which was not as accurate as the test limit at the frequencies in use. It transpired that they had used the same meter for another test on the same kit. Fortunatly voltage was not as critical for that test (5 days in the lab) and the meter had been calibrated only a week before with full report nd no adjustment so we let them do a special calibration check on AC at 60Hz (test in USA) and the frequencie in the test. Fortunatly it all matched and was good enough for that test.
Digital is not automatically better!
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73687 on: October 31, 2020, 12:21:44 pm »
On the Speedometer issue the big problem wirh digital is lag, but not of the display but the drivers brain. 
You have to READ a digital display to tell what the value is. With an analoge pointer nd scale or bargraph display you can ge a very good indication of the value at a glance.
It is  the way or brains have evolved.
This is particuarly important in high workload, multiple display situations like aircraft instrument panels. A pilot can "scan a whole panel of analog gauges in a fraction of a second and spot something out of place. This is why even modern "glass" cockpits still have analog representations as well as digital readouts.
 
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Offline AVGresponding

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73688 on: October 31, 2020, 01:21:49 pm »
If I have to explain one more time when I'm trolling,   :rant:

 :-DD


@Robert, the example with the meters you gave is a problem of observation and basic knowledge, rather than any inherent advantage in either technology.

The human eye is an intriguing piece of evolutionary technology; primitive in some aspects, yet astonishingly advanced in others.

In terms of discerning small changes, a good wobbly pointer will always exceed a DMM, for the simple reason that it effectively has infinite resolution*, whereas the DMM has to measure a defined quantum change before it indicates a change, ie for a 20,000 count DMM the magnitude of the reading must change by 0.01% just to flip the LSD, which may sound like a small amount, but compared to the magnitude of a movement the human eye can detect, it's hopelessly imprecise.

Also as you point out, the brain is evolved to use the information from the eyes in a certain way, which can make it faster reading analog output, though I'd argue training the brain is possible in such a way to make the difference negligible, in certain circumstances.

EDIT: * Assuming zero friction in the movement, and perfect linearity in the return spring. Obviously this isn't possible in practice, though I suspect the effective resolution on a good quality unit would still be enough to make a volt/time nut salivate.
« Last Edit: October 31, 2020, 01:29:37 pm by AVGresponding »
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73689 on: October 31, 2020, 01:41:06 pm »
Granted they are, but there is no blurring in the transition from 1 digit to the next and is still far easier to read at a glance your speed.

I don't know, perhaps a digital meter with a lamp mounted on it could be interesting if the meter display was on when the lamp was on as well.  :-DD :-DD :-DD

 :palm: The year is 2052, those of us who are left are browsing Ebay for TEA, hoping to find a vintage NanoVNA... but then!...

McBryce.

 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73690 on: October 31, 2020, 01:50:22 pm »
If I have to explain one more time when I'm trolling,   :rant:

 :-DD


@Robert, the example with the meters you gave is a problem of observation and basic knowledge, rather than any inherent advantage in either technology.

The human eye is an intriguing piece of evolutionary technology; primitive in some aspects, yet astonishingly advanced in others.

In terms of discerning small changes, a good wobbly pointer will always exceed a DMM, for the simple reason that it effectively has infinite resolution*, whereas the DMM has to measure a defined quantum change before it indicates a change, ie for a 20,000 count DMM the magnitude of the reading must change by 0.01% just to flip the LSD, which may sound like a small amount, but compared to the magnitude of a movement the human eye can detect, it's hopelessly imprecise.

Also as you point out, the brain is evolved to use the information from the eyes in a certain way, which can make it faster reading analog output, though I'd argue training the brain is possible in such a way to make the difference negligible, in certain circumstances.

EDIT: * Assuming zero friction in the movement, and perfect linearity in the return spring. Obviously this isn't possible in practice, though I suspect the effective resolution on a good quality unit would still be enough to make a volt/time nut salivate.

While the regulars will of course know when you're trolling, others will not and walk away with the wrong impression  >:D
Who let Murphy in?

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73691 on: October 31, 2020, 01:53:05 pm »
Granted they are, but there is no blurring in the transition from 1 digit to the next and is still far easier to read at a glance your speed.

I don't know, perhaps a digital meter with a lamp mounted on it could be interesting if the meter display was on when the lamp was on as well.  :-DD :-DD :-DD

 :palm: The year is 2052, those of us who are left are browsing Ebay for TEA, hoping to find a vintage NanoVNA... but then!...

McBryce.


I expect the only reason no one has done this yet is because most DMM are not flat-bottomed or deep enough to allow them to stand on end or accept a batten lamp holder, unlike an old Avo  :-//
« Last Edit: October 31, 2020, 01:54:36 pm by Specmaster »
Who let Murphy in?

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73692 on: October 31, 2020, 01:57:23 pm »
Heads up for the UK guys, our beloved and esteemed  :-DD PM will be addressing the nation at 16:00 Hours, be prepared to batten down the hatches for 4 weeks  :palm:
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73693 on: October 31, 2020, 02:01:58 pm »
Well it's a headless server so YMMV on that  :palm:. Fixed. drm related. Add "nomodeset" and "i915.modeset=0" to the kernel parameters.

Ffuuuuuuck all I wanted to do was program a sodding AVR.

Late to the party: Headless servers have serial consoles. If I could only stop the stupid consumer hardware from using VGA and USB to push out boot messages, I'd be sooo happy.

In my storage, I have a Samsonite classic briefcase that has a all-in-one keyboard/trackpad with PS/2 & USB connections, HP15" 4:3 monitor mounted inside on a hinge so it folds up when I close it, and 12V SLA battery to power everything. Looks like some cheesy bit of sneaky kit out of HACKERS:-DD   I had to make it up for doing service calls for one of my clients; they used early versions of a NUC in a lockbox as interface units for RFID security. As pay was by the ticket (up to a minimum) not time, it paid for itself very quickly.

As of the last time I was actually working in the field, it still saw service at least once or twice a month.

mnem
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73694 on: October 31, 2020, 02:08:04 pm »
While the regulars will of course know when you're trolling, others will not and walk away with the wrong impression  >:D

The story of my life...   :-X


Granted they are, but there is no blurring in the transition from 1 digit to the next and is still far easier to read at a glance your speed.

I don't know, perhaps a digital meter with a lamp mounted on it could be interesting if the meter display was on when the lamp was on as well.  :-DD :-DD :-DD

 :palm: The year is 2052, those of us who are left are browsing Ebay for TEA, hoping to find a vintage NanoVNA... but then!...

McBryce.


I expect the only reason no one has done this yet is because most DMM are not flat-bottomed or deep enough to allow them to stand on end or accept a batten lamp holder, unlike an old Avo  :-//

You just need one with a good tilting bail:

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73695 on: October 31, 2020, 02:10:12 pm »
If I have to explain one more time when I'm trolling,   :rant:

 :-DD


@Robert, the example with the meters you gave is a problem of observation and basic knowledge, rather than any inherent advantage in either technology.

The human eye is an intriguing piece of evolutionary technology; primitive in some aspects, yet astonishingly advanced in others.

In terms of discerning small changes, a good wobbly pointer will always exceed a DMM, for the simple reason that it effectively has infinite resolution*, whereas the DMM has to measure a defined quantum change before it indicates a change, ie for a 20,000 count DMM the magnitude of the reading must change by 0.01% just to flip the LSD, which may sound like a small amount, but compared to the magnitude of a movement the human eye can detect, it's hopelessly imprecise.

Also as you point out, the brain is evolved to use the information from the eyes in a certain way, which can make it faster reading analog output, though I'd argue training the brain is possible in such a way to make the difference negligible, in certain circumstances.

EDIT: * Assuming zero friction in the movement, and perfect linearity in the return spring. Obviously this isn't possible in practice, though I suspect the effective resolution on a good quality unit would still be enough to make a volt/time nut salivate.

While the regulars will of course know when you're trolling, others will not and walk away with the wrong impression  >:D

You say that as if it were a bad thing. ;)

mnem
As long as they walk away... >:D
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73696 on: October 31, 2020, 02:13:42 pm »
Heads up for the UK guys, our beloved and esteemed  :-DD PM will be addressing the nation at 16:00 Hours, be prepared to batten down the hatches for 4 weeks  :palm:

Before lockdown: sitting on my arse in front of computer all day.

During lockdown: sitting on my arse in front of computer all day.

Win  :-+

Just got Watch Dogs: Legion so got even more reason to sit on my arse in front of the computer all day  :palm:
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73697 on: October 31, 2020, 02:16:56 pm »
On the Speedometer issue the big problem wirh digital is lag, but not of the display but the drivers brain. 
You have to READ a digital display to tell what the value is. With an analoge pointer nd scale or bargraph display you can ge a very good indication of the value at a glance.
It is  the way or brains have evolved.
This is particuarly important in high workload, multiple display situations like aircraft instrument panels. A pilot can "scan a whole panel of analog gauges in a fraction of a second and spot something out of place. This is why even modern "glass" cockpits still have analog representations as well as digital readouts.

Precisely; I've made that point several times on this forum, the last time being a couple of days ago.

But there is an extra reason; in some cases the analogue output works where a digital output simply cannot. The classic examples are artificial horizons and compasses. Seeing the "dial" rotate is easy to interpret, whereas a sequence of digits such as 0, 0, 11, 83, 142, 271, 98, 141, 333, 59,.... simply isn't enough to stop you turning into strawberry jam within the next 10 seconds.



There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Online mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73698 on: October 31, 2020, 02:28:18 pm »
Mmmmm... fresh human spread for my morning toast. >:D

mnem
 
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Online Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #73699 on: October 31, 2020, 02:50:40 pm »
It is now (14:51 GMT) the full moon, a blue moon, on All Hallows Eve.

Mnem: knock yourself out.

(Anyone allergic to animated GIFs should probably skip a few pages...)
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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